Header fabrication questions

Not sure if this belongs here or in Sprockets, but I figured "headers is headers" so I'll put it here.

I'm going to be stuffing a GSXR 750 motor into an older Yamaha Warrior quad frame. I'm comfortable with all the frame tubing, motor mounts etc. I'm going to try making my own header though as the original 4-1 unit on the bike will hang down too far under the quad for off-road purposes.

My questions are pretty basic: Is a band saw the tool I need to precisely cut the mandrel bends I'll use, or is there an easier/better way? What's a good way to mock it up before cutting those pricey bends etc?

Not sure on cutting, but some use electrical conduit to mock up the headers and then as a template for the pipes.

Band saw is what you want. Do some practice cuts on scrap material first. If you rotate the tube a little as you cut through it will help keep the ends square.

Old school header guys use a tubing cutter with sharp cutting wheels in all three positions, no rollers. That allows cutting all the way around the tube without having to spin the body of the cutter all the way around, makes it easy to cut in the middle of a u-bend. Just make sure to start the cut carefully so that all three cutters are following the same path.

A chop saw will do the job pretty nicely as well.

Don't cheat, make all of your cuts square to the tube and let the mandrel bends take care of the actual changes of direction.

I've built one set by doing an initial mockup in blue pool hose. It's about the same diameter as (car) primary tubes so you can check the basic stuff like routing and clearance. I then used welding rod to fine-tune the shape, making sure to keep the radii correct to match what's available in mandrels.

Keith, using the blue pool hose is interesting. What if.....you use the hose, then when you get it where you want it, shoot expandable foam in there so the hose can be removed and it'll retain the shape? Then you can bend metal to match?
I've never made a header before, so I'm just tossing that out there.

weedburner wrote: Old school header guys use a tubing cutter...

It's a little tough to get all the wheels to cut on the same line, as mentioned, but it has the additional benefit of giving really nice beveled edges, which are great for welding.

DrBoost wrote: Keith, using the blue pool hose is interesting. What if.....you use the hose, then when you get it where you want it, shoot expandable foam in there so the hose can be removed and it'll retain the shape? Then you can bend metal to match? I've never made a header before, so I'm just tossing that out there.

We tried something like that once. The foam didn't hold up. The blue hose won't hold a specific radius, so it's really only useful if you're looking to decide basic routing. In my case, I was trying to figure where it should exit the body and what in configuration the tubes should enter the collector. The tubes were cut to length.

Then the welding rod step. You have to pay attention here to leave enough room between "pipes".

And of course, the awesome way to do it. Ice Engine Works "header lego".

Yeah, that ICE EW stuff looks killer. I was hoping the foam in the pool hose would work because that ICE stuff is expensive and I'm cheap.

It's not THAT expensive. $400 (these days) for the set I use, and it's paid for itself a couple of times over in both time and material savings. But if I was just doing one and it's wasn't crazy complicated, I'd go with the blue hose/welding rod method I used on my Locost way back when. Worked well.

I know a few people who have put sport bike engines in quads. They usually end up for sale shortly afterwards, since they are generally worthless.

I researched this to death when I was swapping the GSXR1000 in my sports racer for a GSXR1300 Hayabusa.

I can fab, I can TIG, I didn't have that kind of time...

This I learned:

• Speedway Motors is cheap for mandrel bends in steel.

• Look around at what the mini-sprint and sand rail guys are doing. There may be a commercially available solution.

andrave wrote: I know a few people who have put sport bike engines in quads. They usually end up for sale shortly afterwards, since they are generally worthless.

Yes, that's a true statement. Although the same can be said for many, many engine swapped cars. I think it's in the execution and the expectations.
In my case, I have a tired bike with a good motor, and a tired motor with a good quad.
It's mostly for shredding sand, but if it's somewhat trail worthy that's a bonus.

Thanks for all the great help so far guys!

Check your local muffler shop for mandrel bends as well. I found them to be price competitive with just about everyone and no shipping. Plus I could run down and grab another 6" bend if I needed one.

Just curious, why do you need to make a header? Are you trying to pass the exhaust by on the right hand side like most quads do from the factory? Cause most of the ones I've seen got by with the original bike header.

The 4-1 header is too "thick" at the collector and will hang down too far.
My plan is to make sort of an extended 4-2-1 design that will be lower profile and run under the footpegs rather that right under the motor.

pick up a gsxr 600 header say 2002-2004 in Stainless steel (not 1000's there Ti) the 600 has tri Y from factory. I've used several in dwarf cars and mig welded with normal steel wire still working fine. band saw or chain type tubing cutter.

Good tip thank you! I could likely adapt that to mine although my 750 is an old '89 oil-cooled motor.

The head tube conections are same size it will fit.